1. Field of the Invention
The present invention is a heat nozzle designed for use with a portable, handheld seam sealing welding gun for dispensing a molten sealant to join adjacent sheets of flooring.
2. Description of the Prior Art
In laying flooring that is sold commercially in sheets, such as linoleum flooring, adjacent sheets of flooring are positioned side by side and cut to the desired shape. In the past the flooring sheets have been secured to the floor by adhesive compound. To secure the flooring sheets to the floor, the compound is applied to the floor and the cut sheets of flooring are laid in position, one by one. Once each sheet of flooring is laid, the next adjacent flooring sheet is brought into position and pressed against the floor with the linear edges of adjacent flooring sheets residing in mutual abutment.
One major problem with laying sheets of flooring in this manner is that the adhesive bond between the underside of the flooring sheets and the subfloor therebeneath is sometimes inadequate. Quite often areas of the sheets of the linoleum flooring will tend to separate from the subfloor when the adhesive bond between the subfloor and the flooring sheets deteriorates due to age, movement of the subfloor, or improper installation.
The separation of areas of flooring sheets from the subfloor is particularly pronounced at the interfaces between adjacent sheets of flooring. The edges of adjacent flooring sheets which are supposed to reside in firm, mutual abutment, will sometimes tend to rise slightly from the subfloor. This presents both an unsightly appearance and also leads to a significant deterioration of the floor because of the separation that occurs when the edges of adjacent sheets of flooring rise. When separation between adjacent sheets of flooring occurs in this way, moisture, dirt and debris often find their way into the crack that forms between the flooring sheets, thus leading to further deterioration of the floor.
In the floor installation trade the use of fusible plastics to form a seal between the abutting edges of adjacent sheets of flooring has gained increased popular acceptance. According to this technique the edges of sheets of flooring are not cut perpendicular to the plane of the expanse of the flooring as has historically been the practice. Rather, the edges of the flooring are cut so that adjacent sheets of flooring, when moved into abutting relationship, define an upwardly facing, elongated groove where they meet. That is, the sheets of flooring are cut so that the exposed upper surface covers a slightly smaller area than the concealed undersurface, thus providing adjacent surfaces forming a groove or channel between adjoining sheets of flooring. These adjacent surfaces can be bonded together using a fusible thermoplastic applied from above. The color of the thermoplastic is chosen to match the color of the flooring so as to render the demarcation between adjacent sheets of flooring largely undetectable.
Automated machines have been developed for applying a fusible plastic sealant to seams between adjacent sheets of flooring. Such automated machines roll upon the floor and apply a bead of molten thermoplastic along the seam between adjacent sheets of flooring. The heat required is provided by electrical resistance heating. The molten thermoplastic quickly cools and bonds to the adjoining edges of adjacent sheets of flooring. Once the adjoining edges of sheets of flooring have been sealed in this manner, they will not separate from each other, even in the event that the bond between the undersides of the sheets of flooring and the subfloor deteriorates with time. This prevents a noticeable gap from forming between adjacent sheets of flooring.
While automated seam sealing machines of the type described do create firm, durable sealed seams between adjacent sections of sheet flooring, they are quite large, bulky, heavy, and complicated to operate. Furthermore, they are quite expensive so that their cost is well beyond the resources of the average sheet flooring installer.
Therefore, a much more economical type of machine for creating a seam of fused thermoplastic between adjacent sheets of flooring was developed. Specifically, portable, handheld seam welding guns have been available commercially for quite some time. Such handheld guns are sold at only a fraction of the cost of automated seam welding machines. These are also typically electrically powered and melt a thermoplastic bead by means of resistance heating.
Handheld seam welding guns of this type are typically configured with a generally cylindrical body forming the rear portion of the gun and a heat conducting member projecting forwardly from the body along a longitudinal axis. An adapter having a heat concentration nose, typically formed of a highly conductive metal, such as copper or a copper alloy, is mounted on the heat conducting member and includes a heating tip mounting tube. The heating tip mounting tube projects forwardly along the longitudinal axis of the body and has of a narrow, tubular configuration. This type of adapter is often referred to in the trade as a “pencil tip” adapter. The heating tip mounting tube fits into a hollow heating tip.
A conventional, portable, handheld seam welding gun heating tip includes a hollow cylindrical sleeve that fits onto the heating tip mounting tube and another tubular structure that accommodates an elongated length or stick of thermoplastic that is fed into the interior of the heating tip and melted therein. Conventional, portable handheld seam welding guns of this type are manufactured in Europe by Leister Process Technologies, CH-6060 Sarnen, Switzerland. Other, comparable commercial seam welding guns are also available, such as the Zinser K-5 handheld welder that is available from Zinser Schweisstechnik GmbH, Stuttgarter Strasse 145, 73061 Ebersback/Fils, Stuttgart, Germany.
While conventional, handheld, portable seam welding guns of the type described can produce high-quality seams, the rate at which the seam can be filled with sealant utilizing a portable, handheld welding gun is rather limited. Specifically, using a portable, handheld seam welding gun an experienced flooring installer can fill seams between abutting sheets of linoleum flooring with sealant at the rate of about four feet a minute. In contrast, the expensive, automated seam sealing machines of the type described can be operated to fill seams at the rate of about sixteen feet per minute.